Flexible packages are used for containing a wide variety of items, both solid and liquid, such as beverages, lawn products and food products. More and more packages, including flexible packages, are being used for the containment and or dispensing of food, liquids or medical products.
There are major flaws with the current methods of using a single locking member strip of zipper—e.g., Velcro®, press-to-close, or the like—sealed to a web of material in the transverse direction when it is folded over and locked onto itself during package formation. When the closure is attached across the web of material, it is held back from the edges of the material for the section of material where the package lap seal or fin seal will be formed when the package is made. The profile of the zipper, if running both ends into the fin or lap seal, is too thick and will leave gaps in the fin or lap seal where air or product can get in and out of the package.
Referring to FIGS. 1-4, a conventional package 10 utilizing convention closure devices 12 and methods (e.g., zipper, Velcro®, press-to-close, etc.) is shown. The closure device 12 is sealed to the web of material 11 in the transverse direction to the web and folded over and locked onto itself when the package 10 is formed. Those closure devices 12 provided as zipper devices can include front 13 and rear 15 interlockable members and one or more flange portions adapted to seal or otherwise attach to the package.
When the closure 12 is attached across the web of material, it is typically held back or otherwise provide a distance short of the edges 16, 18 of the material for the section of material where the package lap seal or fin seal 20 will be formed when the package 10 is made. The profile of the zipper closure 12, if running both ends into the fin or lap seal 20, is too thick and will leave gaps AG in the fin or lap seal where air or product can get in and out of the package 10.
Moreover, the method of forming a pillow or side gusseted package, is not exact, and leaving the exact amount of space on the ends of the closure to form the correct size fin or lap seal is virtually impossible. Typically, the zipper is actually run a little short so as to make sure none gets in the fin seal 20 and is only as close to the fin seal as reasonably possible (e.g., adjacent or approaching the seal). This process actually leaves a gap AG between the ends of the closure when the package is formed (FIG. 4), where air and small particles of the product that are in the package can pass through. This is not acceptable by many companies, or consumers, as they require a package that is as close to air tight as possible.